What
is Electronics?
Electronics
is the branch of science that deals with the study of flow and control of
electrons (electricity) and the study of their behaviour.
Application
of Electronics
Electronics has made tremendous advancement
during last few decades and our day to day life involves the use of electronic
devices. Electronics has played a major role in every sphere of our life; this
can be proved with the following application of electronics:
Entertainment
and Communication
Availability of economical and fast means
of communication paves the way for progress of a country. Few decades ago, the
main application of electronics was in the field of telephony and telegraphy.
Now, with the aid of radio waves we can transmit any message from one place to
another, without the use of wires. Radio and TV broadcasting offers a means of
both entertainment as well as communication. Today, Electronics gadgets are
widely used for entertainment.
Defense
Applications
Defense applications are completely
controlled by electronic circuits. RADAR that is Radio Detection and Ranging is
the most important development in electronics field. With the help of radar it
is possible to detect and find the exact location of enemy aircraft. Radar and
anti-craft guns can be linked by an automatic control system to make a complete
unit.
Industrial
Application
Electronics circuits are widely being used
in industrial applications such as control of thickness, quality, weight and
moisture content of a material. Electronic amplifier circuits are used to
amplify signals and thus control the operations of automatic door openers,
power systems and safety devices. Electronically controlled systems are used
for heating and welding in the industry. The most important industrial
application is that the power stations which generate thousands of megawatts of
electricity are controlled by tiny electronic devices and circuits.
Medical
Services
Electronics systems are being used by
Doctors and scientists in the diagnosis and treatment of various diseases.
X-rays, ECG, Short eave diathermy units and oscillographs are some instruments
which have been used so far in medical science. The use of electronics in
medical science has grown so extremely and is useful in saving the life of
mankind from a lot of sufferings.
Instrumentation
- Application of Electronics
Electronics instruments such as cathode-ray
oscilloscopes, frequency counters, signal generators, strain gauges are of
great help in for precise measurement of various quantities. Without these
electronic instruments no research laboratory is complete.
Basic
Concepts & Definitions
Voltage: Unit is Volts, Symbol is “V or U”, old symbol was E. Voltage is the "pressure" of electricity, or "electromotive force" (hence the old term E). A 9V battery has a voltage of 9V DC, and may be positive or negative depending on the terminal that is used as the reference. The mains has a voltage of 220, 240 or 110V depending where you live - this is AC, and alternates between positive and negative values. Voltage is also commonly measured in millivolts (mV), and 1,000 mV is 1V. Microvolts (uV) and nanovolts (nV) are also used.
Current: Unit is Amperes (Amps), Symbol is “I”. Current is the flow of
electricity (electrons). No current
flows between the terminals of a battery or other voltage supply unless a load
is connected. The magnitude of the
current is determined by the available voltage, and the resistance (or
impedance) of the load and the power source.
Current can be AC or DC, positive or negative, depending upon the
reference. For electronics, current may
also be measured in mA (milliamps) - 1,000 mA is 1A. Nanoamps (nA) are also used in some cases.
DC: Direct Current. The electrons flow in one direction only. Current flow is from negative to positive,
although it is often more convenient to think of it as from positive to
negative. This is sometimes referred to
as "conventional" current as opposed to electron flow. AC: Alternating Current. The electrons flow
in both directions in a cyclic manner - first one way, then the other. The rate of change of direction determines
the frequency, measured in Hertz (cycles per second).
Frequency: Unit is Hertz, Symbol is Hz, old symbol was cps (cycles per
second). A complete cycle is completed when the AC signal has gone from zero
volts to one extreme, back through zero volts to the opposite extreme, and
returned to zero. The accepted audio
range is from 20Hz to 20,000Hz. The
number of times the signal completes a complete cycle in one second is the
frequency.
Resistance: Unit is Ohms, Symbol is R or Ω. Resistance is a measure of how
easily (or with what difficulty) electrons will flow through the device. Copper wire has a very low resistance, so a
small voltage will allow a large current to flow. Likewise, the plastic insulation has a very
high resistance, and prevents current from flowing from one wire to those
adjacent. Resistors have a defined
resistance, so the current can be calculated for any voltage. Resistance in passive devices is always
positive (i.e. > 0)
1. Category of Electronics
a. Analog
b. Digital
§ Analog contains basic electronics components with circuit designing.
§ Digital contains logical control structure of electronics circuit.
§ Combination of analog and digital makes our life easy and
interesting by providing most preferable gadgets like computer, mobile, TV etc.
§ After completing this module, you are able to troubleshoot the basic
level of IT field’s problem which is most preferable in any IT Industry.
1. Types of Material
a. Conductor
b. Semiconductor
c. Insulator
a.
Conductor
A conductor is a medium through which an
electric current will easily flow. Example:
Silver, copper, gold, aluminum, iron, steel is called conductor. 100%
flow of current is seen in conductor.
b.
Semiconductor
A solid compound that conductor electricity well at high temperatures but practically not at all at low temperatures is known as Semiconductor.
Example: Germanium and silicon. 50% of
conduction of seen in Semiconductor.
c.
Insulator
An Insulator is a material that restrict the transfer of either heat or electricity. Example: - glass, rubber, oil, asphalt, wood
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